Air volume control mechanism



June 1958 H. A. TUBBS AIR VOLUME CONTROL MECHANISM 2 Sheets-Sheet 1 Filed Sept. 27, 1954 FIG. 8.

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INVENTOR. HOWARD A. TUBBS FIG. I.

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Attorneys June 17, 1958 H. A. TUBBS 2,839,001

AIR VOLUME CONTROL MECHANISM 2 Sheets-Sheet 2 Filed Sept. 27, 1954 INVENTOR.

HOWARD A. TUBBS Attorneys Un ted States PatenrQ 2,839,001 AIR VOLUME CONTROL MECHANISM Howard A. Tubhs, Whitewater, Wis.

' Application september 27, 1954, Serial No. 458,303 i Claims. c1. 103-6 fined above the liquid in the tank and this layer of air serves as an expansible cushion. As the air is slowly absorbed in the liquid, the amount of air is gradually decreased so that the air cushion is reduced and is replaced by the liquid. As the air cushion decreases the pump will be required to operate more frequently to build up the required pressure in the tank.

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mechanisms that may be injured by handling or through extensive operation of the pumping system.

The drawings furnished herewith illustrate the best mode presently contemplated of carrying out the invention as set forth hereinafter.

In the drawings:

Figure l is a schematic representation of a pumping system employing the air volume control mechanism of the present invention;

"Fig. 2 is an enlarged fragmentary vertical sectionof the air volume control as connected to the'storage tank showing conditions when the pump is idle; i r

Fig. 3 is a view similar to Fig. 2 showing the conditions during the pumping cycle in which the water in the tank is at a level below the conduit to the air volume control and with an adequate air cushion in the tank;

Fig. 4 is a view similar to Fig. 2 but showing theconditions during the pumping cycle-with the water in-the tank at a level above the conduit to the air volume control due to an inadequate air cushion in the tank;

Fig. 5 is a view similar to Fig. 4 showing the control 1 immediately after the pumping cycle has been completed The present invention is directed to an air volume control mechanism which automatically supplies air to a liquid storage tank to maintain a predetermined cushion of air'in the tank.

i The air volume control mechanism of the invention in general comprises a hollow casing formed of matching upper and lower sections. The sections are formed with a generally conical shape with the base portions of the conical sections attached together.

' The-upper section of the casing communicates with the liquid storage tank through a restricted opening at which communicates with the suction side of a pump. The outlet is adapted to be closed off by a spherical float which seats in a flexible cup-shaped valve seat at the outlet. The spherical float is free to move within the casing and when the pump is idle, the casing is full of water so that the float will be at the upper end thereof. When the pump is started, suction is created at the outlet and water isdrawn from the casing through the outlet which results in the float moving downwardly within the casing. As the water isdrawn out of the casing the float is guided onto the valve seat by the conical side walls of the casing. "lDepending on the water level in the storage tank, air is either drawn through the restricted opening from the tank to the casing or air is drawn through the check valve from the atmosphere to thecasing. On completion of the pumping cycle, water is forced into the casing through the outlet which forces the float valve from its seat and the casing is then filled with water; The water entering th'e casing drives the air from the casing into the tank to f orm a cushion above the water contained therein. v The combination of the conical shaped casing and the freely disposed float provides a simple means of regulating theflow-of fluid in an air volume control mechanism. The valve seat for the float valve is of simple constructionand with the float provides a positive seal between.

in both'of the conditions illustrated in Figs. 3 and 4;

Fig. 6 is a horizontal section of the air volume control taken on line 6-6 of Fig. 5; Fig. 7 is an enlarged fragmentary vertical section of the restricted opening between the storage tank and the air volume control chamber; and

Fig. 8 is an enlarged fragmentary vertical section of the float valve disposed on the valve seat.

J The drawings illustrate a pumping system for supplyling a liquid from a well to a liquid storage tank. The pumping system in general comprises a storage tank 1 to store the liquid,'sueh as water, under pressure. The water is supplied to the tank through pipe 2 by apump 3 which is driven by motor 4. The water is supplied to the pump through a conduit pipe 5, connected to a source of water. The motor is actuated by a switch 6 which is responsive to the pressure in tank 1 and serves to connect the motor 4 to a source of electric current.

As the pressure within the tank 1 falls below a predetermined value, thepressure switch 6 is closed and the motor is actuated to start pump 3 and build up the pressure in the tank to an upper predetermined limit. When the pressure reaches the upper limit the switch 6 automaticallyopens and the motor is stopped. The water level, within the tank 1 fluctuates between an upper and lower level which correspond to the upper and lower pressure limits. The upper liquid level in the tank is selected so as to provide a'large air cushion or space above the liquid whileat the same time provide a comparatively large amount of liquid storage in the tank. i

When the liquid level in the tank tends to rise above the maximum limit due to the absorption of air in the liquid, air is automatically admitted to the tank each time the pump is cycled by means of an air volume control mechanism indicated generally by 7, to retain the desired level of liquid. A pipe 8 connects the air volume control to the suction side of the pump 3, and a pipe 9 provides communication between the air volume control mechanism 7 and the tank 1 at the position of the lower liquid levelcorresponding to the lower pressure limit.

The air volume control mechanism 7 illustrated in the drawings, comprises a hollow casing which is formed of two generally conical sections 10 and 11 which are, se-' curedtogether to form a chamber 12. The base portions, of the sections 10 and 11 are provided with matching flanges 13 which are secured together by bolts 14. The casing may be ofdifferent shapes and constructed of one or several parts.- Internal guide ribs 15 extend longifloat later to be described herein.

,1. Section is provided with a small axial opening 16,

as best seen in Fig. 7, and a chamber 17 which communicates with opening 16. One side of chamber 17 is closed by a threaded plug 18. A passage 19 is formed in casing section 10 which extends generally normal to the axis of the section and provides communication be tween another side of chamber 17 and a threaded aperture 20 which threadedly receives the end ofpipe 9.

. Passage of fluid between the tank and the chamber 12 is controlled by ball check valve 21 which is disposed in vertically extending chamber 17 and is adapted to rest in a cup-shaped valve seat 22 that defines opening 16 and which may be integral with the wall defining chamber 17 or a separate member. As shown in Fig. 7, the ball 21 has peripheral grooves 23 or other means to provide an imperfect seal between the ball and its seat so that when the ball is disposed on the valve seat 22 a restricted opening will be provided between chamber 12 and chamber 17. The restricted opening provided by leaky valve 21 permits rapid flow of air in either direction between tank 1 and chamber 12 but restricts the rapid flow of liquid from tank 1 to chamber 12. Any other type of check valve having a restricted opening when seated may be employed in place of the valve 21 and valve seat 22. The ball or the seat, for example, maybe imperfect.

Air is introduced into chamber 12 from the atmosphere through an opening 24 which is formed in the lower section 11 of the casing. The opening 24 is disposed at the vertical center of the casing. The flow of air through opening 24 is controlled by a check valve 25 which is shown as biased into engagement with valve seat 26 by 4 form to any irregularities in the surface of the float valve and tension of the flexible seat forces the ball oil the seat when the suction is released.

Chamber 12 is normally full of liquid when the pump is idle and the float valve 313 is disposed in the upper end of chamber 12 as shown in Fig. 2. The liquid level in the storage tank 1 is at its upper limit, substantially above the connection to pipe 9.

spring 27. Spring 27 is maintained within opening 24 by an enlargement 28 of a rib 15. However, the ball may close the valve opening by its own weight or be seated on the opening by other means.

As the pressure in chamber 12 decreases below a predetermined value, the atmospheric pressure will be suflicient to overcome the force of spring 27 or other means of closing the valve and open valve 25 to admit air to chamber 12.

The pipe 8 which provides communication between the chamber 12 and the suction side of the pump is thread-. edly engaged in an outlet 29 formed in the lower end of section 11. The flow of liquid through the outlet is con-. trolled by a generally spherical float valve 30 which is adapted to seat on a flexible cup-shaped valve seat 31 disposed atthe entrance to outlet 29 within a generally cylindrical cup-shaped member 32 suitably secured to the cas-v ing. The float valve 30 may be of any shape but it is necessary that the valve be free to be moved directly by the liquid.

Float valve 30, illustrated in the drawings, is composed of any material which can be formed into a spherical con! figuration and which will float on the liquid employed in the pumping system. As the central portion of the casing has a substantially greater diameter than that of the floatvalve 30, the float valve is free to move within the chamber 12 and rises and falls within chamber 12 with variations in the liquid level in the chamber. The generally conical side walls of the lower casing section 11 and guides 15 serve to guide the float valve 30 onto the valve seat 31 as the float moves downwardly within the casing. If the casing is constructed of a diflerent shape, for example cylindrical, other guide means than that described may be provided.

The flexible valve seat 31 has a lip which extends upwardly within chamber 12. The lip is generally conical in shape and the float valve 30when seated engages the inner surface of the upper end of the lip to provide a fluid tight seal between chamber 12 and outlet 29. Increased suction through pipe 8 correspondingly increases the seal-v ing engagement of the float valve 30 and seal 31. The

flexible nature of the seat permits the seal to readily con- If the air cushion in the tank is adequate and water is then drawn from the tank, the switch 6 is not closed to actuate the pump until the pressure within the tank reaches its lower limit which pressure condition occurs when the water level in tank 1 has decreased to a position approximately as shown in Fig. 3 wherein the water level is about in line with pipe 9.

With the pump then placed in operation, suction is created in pipe 8 which draws the liquid out of chamber 12 through outlet 29 and air from tank 1 is then forced from tank 1 through pipe 9 and grooves 23 in ball valve 21 into chamber 12. As the water flows downwardly out of chamber 12 the float valve 30 moves downwardly and when the water has been displaced from chamber 12 the float is disposed on seat 31. During the remainder of the pumping cycle the float valve 30 is disposed on seal 31 thereby closing chamber 12 to the pipe 8.

On completion of the pumping cycle the system reaches a condition of pressure equilibrium whereby the pressurein pipe 8 is the same as the pressure in pipe 9 and tank 1. Liquid in pipe 8 therefor rises and unseats the float valve 30 and enters chamber 12. The liquid entering chamber 12 forces the air upwardly through opening 16 and pipe 9 to tank 1, as shown in Fig. 5.

The air is thereby restored to the tank and a proper 3.11 cushion is maintained above the liquid. Under the conditious described, no air is drawn from the atmosphere into chamber 12 and tank 1 through valve 25.

However, as air in tank 1 is absorbed in the liquid over a period of time so that the air cushion is decreased, the liquid within the tank rises above the level of the liquid shown in Fig. 2. In this situation, if water is drawn from tank 1 the switch 6 will close at its lower pressure limit to start the pump, at which pressure limit the liquid level is then substantially above conduit 9 as shown in Fig. 4. With operation of the pump and the subsequent suction in pipe 8, liquid is drawn out of chamber 12. The liquid from the tank cannot pass through the restricted opening in ball valve 21 fast enough to equalize the pressure within chamber 12, thus a partial vacuum will be created. At this time air from the atmosphere will pass through check valve 25 to chamber 12 to equalize the pressure. During the time when the partial vacuum is present in chamber 12, water may seep through grooves 23 in ball valve 22, but this flow is small and insuficient to equalize the outward flow of liquid through outlet 29.

When the liquid has been displaced from chamber 12 float valve 30 will be disposed on valve seat 31 and the chamber 12 will be substantially full of air.

On completion of the pumping cycle water passing through pipe 8 unseats float valve 30 and forces the air in chamber 12 upwardly through opening 16 and pipe 9 to tank 1. The flow of air through opening 16 unseats check valve 21 from seat 22, thereby providing a relatively unrestricted flow of air through opening 16 to provide for rapid passage of air to the tank. The rapid flow of air to the tank from chamber 12 is desirable in order to maintain the air cushion in the tank particularly when the pump is cycled at short intervals. Thus, air from the atmosphere is supplied to the tank to increase the air cushion in the tank and maintain the proper liquid level in the tank.

Although the air volume control mechanism is'shown as adjacent to the tank, the air volume control may be disposed in a remote location below the tank. It is only necessary that the conduit between the tank and control be connected to the tank at the minimum liquid level in the tank.

The present invention maintains the proper proportion of air and liquid in the storage tank in an automatic manner to provide an adequate air cushion in the tank at all times and maintain a predetermined liquid level therein.

Various modes of carrying out the invention are contemplated as within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In a fluid pressure system having a pump to supply liquid to a liquid supply tank and an air volume control to supply air to said tank, a conduit connecting said control to the tank, a freely movable ball check valve disposed in said conduit and providing for unrestricted flow of air through the conduit in either direction but restricting the flow of liquid from the tank to the control, a check valve secured to the control to admit air to said control, means connecting said pump to the tank, a second conduit extending between the control and the suction side of the pump, and a second valve disposed in the control and adapted to close ofi the second conduit to prevent air from entering the suction of the pump from the control when the control is substantially drained of liquid, the said first named conduit being the sole connection between the control and tank and the second conduit being the sole connection between the control and said pump.

2. In a fluid pressure system, a liquid storage tank, a pump to supply liquid to said tank, an air volume control to supply air to said tank, a horizontal conduit connected to said tank and terminating in a vertical section connected to said control, a freely movable leaky check valve disposed in the vertical section connected to said control for up and down movement and providing for unrestricted flow of air through the conduit in either direction but restricting the flow of liquid from the tank to the control, a check valve secured to the control to admit air to said control, means connecting the pump liquid to the tank, a hollow air volume control casing defining a closed chamber, a lower connection extending between an outlet at the lower portion of said casing and the suction side of the pump with the pump being the sole means for providing sub atmospheric pressure within the casing and the lower connection 'being the only comto the tank, a second conduit extending between the control and the suction side of the pump, and a float valve disposed in the control and adapted to close off the second conduit to prevent air from entering the suction of the pump from the control when the control is substantially drained of liquid, the said first named conduit being the sole connection between the control and tank and the second conduit being the sole connection between the control and said pump.

3. In a fluid pressure system for supplying air to a liquid storage tank to replace air absorbed in the liquid and to maintain the desired liquid level in the tank, a pump connected to the tank and to a source of liquid to supply liquid to the tank, a hollow air volume control casing defining a closed chamber, an upper connection extending between the upper portion of said casing and the storage tank, a lower connection extending between an outlet at the lower portion of the casing and the suction side of the pump with the pump being the sole means for providing sub-atmospheric pressure within the casing and the upper connection being the sole connection between the casing and tank, freely floating valve means in said upper connection permitting unrestricted flow of air between the tank and control but restricted flow of liquid from the tank, a float valve freely disposed to float on the liquid in the chamber inside said casing, a flexible cup shaped valve seat disposed at said outlet to seat said float, said seat projecting upwardly from the outlet and closing about said float on the seating thereof when the chamber is subjected to suction by said pump and substantially drained of liquid to thereby municati-on between the pump and air volume control, an-

upper connection extending from said tank and joined to the casing by a vertically disposed extension with the upper connection and vertical extension thereof being the sole connection between the tank and easing, a valve seat located between the casing and upper connection, a leaky valve disposed in said vertical extension for passage of air in either direction through the upper connection and free to raise vertically from the valve seat when water flows from the casing to the tank, a check valve disposed in an aperture in the casing and adapted to admit air to the casing from the atmosphere when the pressure in the casing chamber is below atmospheric, a lower connection extending between an outlet at the lower portion of the casing and the suction side of the pump with the pump being the sole means for providing sub-atmospheric pressure within the casing, and a float valve disposed in the casing chamber and adapted to freely float on the liquid therein and to close off the outlet to the pump when the chamber is subjected to a predetermined degree of suction by said pump and substantially drained of liquid to thereby prevent air in the chamber from entering the suction of the pump, and said leaky valve in the upper connection when seated on the valve seat being adapted to restrict the flow of liquid from the tank to the chamber when the liquid level in the tank is above the upper connection and when said chamber is subjected to suction by the pump thereby permitting air to enter the chamber through said check valve when the liquid level in the tank has fallen below said upper connection.

5. In an air volume control mechanism for supplying air into a liquid storage tank to replace air absorbed in the liquid and to maintain the desired liquid level in the tank with the liquid being supplied to the tank by a pump, a hollow casing defining a closed chamber, a generally spherical float valve freely disposed to float on the liquid in the chamber, said casing having an outlet in the lower end thereof providing communication with the suction side of a pump, a flexible upwardly extending generally frusto-conical valve seat disposed at said outlet with the end portion of least diameter of the seat facing said outlet, and guide means associated with the casing separate from the float valve to guide the valve to its seat with said float valve being adapted to engage the inner periphery of said seat and said seat conforming to the contour of the float valve to provide a fluid-tight seal between said chamber and said outlet when the chamber is subjected to sub-atmospheric pressure by said pump and substantially drained of liquid to thereby prevent air in the chamber from entering the suction of the pump.

References Cited in the file of this patent UNITED STATES PATENTS 2,457,863 Burks Ian. 4, 1949 2,509,130 Burks May 23, 1950 2,520,794 Brady Aug. 29, 1950 FOREIGN PATENTS 980,591 France May 15, 1951 

